1. Field of the Invention
The present invention relates to well completions. More particularly, the present invention relates to supplying power and/or control to downhole components in a wellbore. More particularly still, the present invention relates to the placement of a power/control source in a wellbore on a first tubular
2. Background of the Related Art
In the drilling, completion and operation of hydrocarbon wells, components are routinely inserted into a wellbore and then remotely operated from the surface of the well. Some of the components remain in the wellbore and others are removed after their use often times, multiple components are simultaneously in use in a wellbore. Components include valves, sensors, flow control devices, diagnostic equipment, indexers, seismic devices, downhole pumps, tractors, multiplexers, expander tools and cutting tools, to name a few. All of the foregoing are typically run into the wellbore on a string of tubulars. Additionally, all of the foregoing may rely upon either electrical or fluid power for at least some part of their operation.
Valve-type components used and operated remotely in a wellbore include deployment valves, which are one-way, flapper valves designed to prevent the upward movement of fluids in a wellbore towards the surface of the well. Auto-fill float valves are installed at the lower end of a tubular string as it is inserted into a newly formed borehole. They typically include a valve to permit fluid to enter the string as it is inserted into the wellbore but to later prevent the flow of cement into the string after the cement has been pumped out of the bottom of the string and into an annular area created between the outside surface of the string and the borehole therearound. Another downhole valve is designed to control the flow of fluid into production tubing at a junction between a central wellbore and at least one lateral wellbore extending therefrom. Still other downhole valves include sliding sleeve arrangements wherein ports in a valve body and/or a sleeve are selectively exposed or covered to restrict the flow of fluid through the valve.
Sensors and monitors used downhole include devices to measure well parameters at specific locations in the wellbore. The parameters can include temperature, pressure, flow rate, and other characteristics of the well, the reservoir or the fluids in the reservoir. Sensing components used in a wellbore include devices or sensors to obtain information related to seismic activity at various places in the wellbore. The data is subsequently relayed to the surface of the well. Additionally, diagnostic functions in a wellbore are performed by devices placed in the wellbore which can be electrically connected to another component to diagnose and identify any problems associated with that component in the wellbore.
Other valves used in wellbores are for gas lift operations where gas is injected from the surface of the well through a casing annulus into production tubing through a valve mechanism located above the bottom of the tubing. The gas mixes with production fluids and lightens the flow stream, thereby assisting in bringing production fluids to the surface. Yet another type of valve used in a wellbore relates to the injection of chemicals or other fluids used to treat the wellbore or the surrounding hydrocarbon-bearing formations.
Other downhole components which are controlled from the surface of the well are mechanical in nature and include index tool guides with a shiftable member that shifts from a first position in axial alignment with the center line of the tool body to a second position in which the member is at an angle to the axial centerline of the tool body. The device is run into the wellbore on a tubular and then is remotely actuated to cause the member to assume the second, non-axial position. Yet another example of a mechanical device is a controllable profile. Profiles are routinely used on the inner surface of a tubular to be later engaged by a mating profile inserted into the tubular. The profiles are especially useful in locating and fixing a component in a wellbore at a predetermined, desired location. Controllable profiles are those with shapes that can be changed based upon a signal or manipulation from the surface of the well. Controllable profiles are especially useful to accommodate different tools that might be inserted into the wellbore. Typically, the profiles are changed using wireline, hydraulics or electrical power.
Other downhole devices are used for axial motion in the wellbore. For example, tractors provide axial movement to wellbore components and tubulars when gravity alone is insufficient or when movement cannot be imported from the surface of the well. For example, a tractor is especially useful when an upwards motion must be produced or when a string of tubulars or a component must be moved in a horizontal or lateral wellbore. The tractors typically operate from a source of pressurized fluid supplied from the surface of the well. Similarly, expander tools now exist which can be run into a wellbore on tubing and then, through the use of pressurized fluid, can expand the inner and outer diameter of a tubular therearound pasts its elastic limit. The expander tools use radial extendable rolling members having a piston surface acted upon by pressurized fluid delivered from a tubular string.
Because wellbores may be thousands of feet deep and because lateral and horizontal wellbores are common in today's hydrocarbon wells, components are routinely needed at remote locations in a wellbore. Because the components must be powered, operated and/or monitored from the surface of the well, power lines and/or control lines must extend back to the surface of the well, typically in the interior the tubular transporting the component. In addition to the expense of the lines themselves, the number and sheer length of the control and power lines creates problems with their use. The presence of the lines in a tubular necessarily obstructs the inside of the tubular and limits its use. Also, deeper wellbores and longer lines increase the complicated process of inserting the lines into the wellbore behind the component and increases the chance the lines will become tangled or otherwise damaged during their insertion, operation or removal. Also, each component requires its own lines creating a tangle of lines in a wellbore utilizing multiple components.
There is a need therefore, for an apparatus and method to supply operating power to a downhole component without the need for separate power lines extending from the surface of the well to the components in the wellbore. There is an additional need for methods and apparatus to control downhole components without the need for separate control lines extending from the components back to the surface of the well. There is a further need for flexible methods and apparatus, which permit downhole components to be operated and controlled at various locations within the wellbore. There is yet a further need for methods and apparatus to provide operation and control of wellbore components without the need for control and power lines running from the surface of the well to the component within the same tubular as the component. There is yet a further need for methods and apparatus including a ready source of power and/or controlling means for a downhole component which is lowered into the well without its own control and power lines. There is a further need for a source of power and control which can be utilized by multiple downhole components or by separate components at different times over the life of the well.